GM Service Manual Online
For 1990-2009 cars only

Special Tools

J-21177-A Drum-to-Brake Shoe Clearance Gage

Warning: Refer to Brake Dust Warning in the Preface section.

  1. Apply and fully release the park brake.
  2. Verify that the park brake pedal releases completely.
  3. • Turn ON the ignition. Verify the BRAKE indicator lamp is off.
    • If the BRAKE indicator lamp is on, ensure the park brake pedal is in release mode and has fully returned to the stop. Remove the slack in the front park brake cable by pulling downward on the cable.
  4. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle.
  5. Remove the rear tire and wheel assemblies. Refer to Tire and Wheel Removal and Installation.

  6. Object Number: 1862259  Size: SH
  7. Loosen the locknut (1) at the park brake cable equalizer to relieve tension on the park brake system.
  8. Remove the rear brake rotors. Refer to Rear Brake Rotor Replacement.

  9. Object Number: 177200  Size: SH
  10. Set the J-21177-A Drum-to-Brake Shoe Clearance Gage inside of the park brake drum (1) at the widest point.
  11. • Place the contacts on the tool to the widest point of the drum.
    • Tighten the set screw on the tool to ensure the proper measurement when removing the tool from the drum.

    Object Number: 177201  Size: SH
  12. Position the J-21177-A Drum-to-Brake Shoe Clearance Gage over the park brake shoe (1) at the widest point.
  13. Turn the adjuster screw until the park brake shoe just contacts the J-21177-A Drum-to-Brake Shoe Clearance Gage .
  14. Repeat steps 7-9 for the opposite side.
  15. Install the rear brake rotors. Refer to Rear Brake Rotor Replacement.
  16. Install the rear tire and wheel assemblies. Refer to Tire and Wheel Removal and Installation.

  17. Object Number: 1862259  Size: SH
  18. Adjust the park brake by turning the locknut (1) at the equalizer while spinning both rear wheels. When either rear wheel starts to drag, back off the locknut one full turn.
  19. Lower the vehicle to curb height.
  20. Apply the park brake, then inspect for rotation of the rear wheels. If the rear wheels rotate during this inspection, then readjust the park brake shoes.
  21. Release the park brake. Verify the rear wheels rotate freely.
  22. Lower the vehicle.